1. Field of the Invention
The present invention relates to a motor and a recording disc driving device, and more particularly, to a motor which increases an unmating force between a shaft and a rotor hub and prevents an adhesive from flowing out of the shaft and the rotor hub when the rotor hub is forcibly inserted onto the shaft to be fixed with the adhesive, and a recording disc driving device having the same.
2. Description of the Related Art
In a small-sized spindle motor used in a recording disc driving device, a hydrodynamic bearing assembly is used. Oil is provided between a shaft and a sleeve of the hydrodynamic bearing assembly, and the hydrodynamic bearing assembly is a mechanism supporting the shaft through hydrodynamic pressure formed by the oil.
Recently, as the performance of recording disc driving devices has improved, demand for low current consumption, low Non-Repeatable Run Out (NNRO), impact resistance, and vibration resistance has rapidly increased.
To solve a problem in which oil overflows to the outside of a hydrodynamic bearing assembly due to a high-speed rotation of a shaft, studies on oil sealing have been continuously conducted.
An oil sealing portion may be formed on a thrust plate and an inner surface of a stopper ring for fixing the thrust plate. In this case, when a rotor hub is forcibly inserted onto the shaft, oil may overflow to a front side of the stopper ring to be mixed with an adhesive provided between the rotor hub and the shaft.
When the oil overflows to flow into an insertion surface between the rotor hub and the shaft, the adhesive does not properly harden. In this case, the rotor case may be separated.